Abstract: Herbicide efficacy, coverage, and retention were evaluated for spray applied through Drift Guard, Turbo TeeJet, AI TeeJet, and TurboDrop drift-reducing nozzles compared to a conventional flat-fan nozzle. Percentage spray coverage detected on water-sensitive cards was greater for conventional and Drift Guard nozzles than for Turbo TeeJet, AI TeeJet, and TurboDrop nozzles. Spray without adjuvants was retained better by redroot pigweed for treatments applied with conventional and Drift Guard nozzles than Turbo TeeJet, AI TeeJet, and TurboDrop nozzles. However, spray with adjuvants was retained similarly for all nozzle types when averaged over spray adjuvant and two weed species. The efficiency of spray retention was greater for spray applied in 47 than in 190 L/ha spray volume for all nozzles. Paraquat and glyphosate, representing contact and translocated herbicides, respectively, provided similar grass species control for all nozzle types, regardless of spray volume. Paraquat and glyphosate were also equally or more effective in 47 compared to 190 L/ha spray volume.
Nomenclature: Glyphosate; paraquat; common lambsquarters, Chenopodium album L. #3 CHEAL; foxtail millet, Setaria italica (L.) P. Beauv.; oat, Avena sativa L.; proso millet, Panicum miliaceum L.; redroot pigweed, Amaranthus retroflexus L. # AMARE.
Additional index words: Application methods, droplet size, spray coverage, spray drift, spray retention, spray volume.
Abbreviations: ATV, all-terrain vehicle; MVO, methylated vegetable oil; NIS, nonionic surfactant; VMD, volume median diameter.